The invention relates in particular to a ski in which a sheath or casing of preferably elastomeric plastic material is molded on to the top side and the side surfaces of a ski blank, said ski blank usually comprising strip layers, core, outward sole and possibly steel edges.
A structural configuration of that kind for skis is known, in which the sheath or casing is usually integrally molded on to the rough ski, more specifically in a mold into which the rough ski is fitted, whereupon, after the mold is closed, the material of the sheath or casing is introduced into the remaining mold cavity which corresponds to the sheath or casing. A preferred configuration of that process is the RIM (Reaction Injection Molding) process by means of which polyurethane or components thereof, isocyanate and polyol, which are mixed together and with a dyestuff in the injection head, are injected into the mold cavity. Operation is generally effected using pressures (in the mold cavity) of between 2 and 15 bars. If, as is preferred, the result is to be an elastomeric polyurethane sheath, that can be achieved by virtue of the choice and adjustment of the components of the polyurethane.
The object of the present invention is in particular that of improving skis of the design configuration set forth in the opening part of this specification, more specifically above all in regard to the mechanical-dynamic characteristics of the ski.
Primarily the problem of the invention is that of substantially optimizing the bending characteristics of skis to eliminate harmful influences of the clamped ski boot on the bending characteristic.